Vehicles, such as trucks and station wagons, have a closure member, such as a tailgate, pivotally mounted between body side panels at the rear of the vehicle. The closure member pivots about a hinge axis between horizontally open and vertically closed positions. For instance, in a truck, a tailgate in the closed or up position serves as the rear wall of the cargo bed of the truck. In the open or down position, the tailgate is out of the way to enable loading and unloading of the cargo bed.
Typically, tailgates may be removed from trucks with quick connection fittings. Usually, the quick connection fittings are designed so that the tailgate is removable from the truck when the tailgate is pivoted to a partially open tailgate removal position. For example, the tailgate may include hinge pins extending outwardly along the hinge axis. The hinge pins removably connect into journals mounted on brackets carried on the truck body. When the tailgate is pivoted to the tailgate removal position, at least one of the hinge pins slips through a slot in the connecting journal as the tailgate is lifted at one end from the truck body.
For some operators, handling the weight of the tailgate during opening and closing movements may be too much of a burden. Trucks are becoming more popular with a wider audience of operators than ever before. Operators of all sizes and shapes and both genders use and enjoy trucks. Accordingly, it is advantageous to provide an assist device which may be installed in a pivotable tailgate for assisting in opening and closing the tailgate while permitting quick removal of the tailgate from the truck body.
U.S. Pat. No. 5,358,301 ("the '301 patent") discloses a counterbalance mechanism for a removable tailgate which assists with opening and closing the tailgate while permitting removal of the tailgate from a truck body. The counterbalance mechanism includes a torque rod having a crank end anchored to the tailgate for pivotal movement therewith and a stationary end. A receptacle mounted on the truck body captures the stationary end of the torque rod to restrain pivotal movement thereof. When the tailgate is moved away from a tailgate removal position, the torque rod is torsionally wound and urges the tailgate back towards the removal position. The receptacle captures the stationary end with a releasable slip-fitted connection to permit the tailgate and the torque rod to be removed from the truck body.
A primary disadvantage associated with the '301 patent is that in the various embodiments disclosed therein either the tailgate pivots on the torque rod itself or an end of the torque rod must be aligned with a receptacle on the truck body at the same time as the pivot pins at opposite sides of the tailgate are being aligned with the trunions on the vehicle body. In the first case, the torque rod is an essential component providing the pivotal connection between the tailgate and the truck body and thus is not an option. In short, instead of using hinge pins or shafts to pivot, the tailgate pivots on the torque rod. Thus, the torque rod must be installed for the tailgate to pivot.
In the second case, the tailgate uses hinge pins and trunions for pivoting. However, the torque rod is assembled to the tailgate in a complex and intricate manner. For example, during assembly of the tailgate, the stationary end has to be aligned with an aperture on the lower edge of the tailgate while the anchoring end is aligned with a reinforcement plate located inside the tailgate. All of the aligning must be performed while the torque rod is deep within the interior of the tailgate. This procedure is too difficult for rapid assembly. Moreover, many additional elements are required to assemble the torque rod to the tailgate.